The Stig Hill Test is probably valid for judging the quality of your brakes.
I'd modify it to avoid a mandatory stop sign at the bottom, though...
I generally avoid using the rear brake unless I must... sand/gravel, or need for a qwik stop.
Mostly used to keep the tail in line with the front.
It's far easier to replace front disk brake pads than rear shoes !
If you hear squeaking in the rear drum you should dismantle for inspection.
Metallic noise when applying the rear brake is strong reason to dismantle for inspection ASAP !
There is no 'squealer' indicating wear on rear mc brake shoes, that I am aware of...
redk